Flat brush

Across the global paint brush manufacturing sector, cost optimization is a constant priority. For decades, manual workshops have relied on two straightforward tactics to cut bristle material costs: increasing wedge thickness inside the ferrule, or trimming bristle length shorter. These adjustments work well with hand assembly, where workers can compensate for irregularities with manual fitting — but they create hidden quality risks when production shifts to fully automated lines. One critical, often overlooked metric is the ratio of wedge thickness to ferrule wall thickness. Based on years of field production data from Hengyu automation lines, we recommend keeping this ratio below 0.6 for stable, high-quality output. When the ratio exceeds 0.6, the brush head commonly develops what the industry calls a “fish mouth” defect: the bristle tip splits open into a gaping, uneven shape, much like a fish’s open mouth. Beyond poor aesthetics, this flaw causes uneven paint distribution, visible brush strokes, and higher bristle shedding during use. Worse, it creates a perception of cheap, corner-cutting quality — as if the manufacturer skimped so much on bristles that they cannot even fill the ferrule tip properly. Industry benchmarks for premium paint brushes require a uniform, dense bristle front with no visible gaps, a standard hard to maintain with over-thick wedges in high-speed automated production. The second common cost-cutting measure — shortening bristle length — also has strict limits in automated manufacturing. Unlike human hands, which can adjust packing tension and depth on the fly, precision tufting machines operate on calibrated, repeatable parameters. If bristle retention depth inside the ferrule is too shallow, the bristle bundle loses its structural anchor, leading to loose filaments, inconsistent tip shape, and premature shedding under normal use. Our field testing and client production data show that a minimum retention depth of 7–9 mm inside the ferrule is necessary to form a stable, durable bristle foundation. This aligns with industry standards that measure tuft pull-out strength as a key durability metric; insufficient embedment depth directly reduces pull resistance and shortens brush service life. For manufacturers transitioning to automation, the goal is not to abandon cost control — but to replace guesswork with data-backed design rules. Staying under the 0.6 wedge-to-ferrule ratio and maintaining 7–9 mm of bristle retention depth allows producers to optimize material usage without sacrificing appearance, performance or brand reputation. At Hengyu Automation, we work closely with each client to calibrate machine parameters and product design for their specific brush models, balancing cost efficiency with consistent, market-ready quality.

After years of on-site commissioning and after-sales support for hundreds of paint brush manufacturers worldwide, we have summarized the most frequently asked operational questions about our paint brush head machines. Most of these concerns are not equipment faults, but common adaptation issues during production setup. Below we explain the root causes in detail and share field-proven solutions to help you minimize downtime and maintain stable output.   First, noticeable machine vibration during operation. Slight vibration is an inherent characteristic of high-speed automated machinery and will not affect normal production quality or equipment service life. Extra vibration during initial trial runs usually occurs because the large anti-vibration foot pads are not installed during workshop commissioning. We include a complete set of heavy-duty foot pads with every machine shipment. If vibration remains a concern for your production environment, simply reducing the operating speed appropriately will effectively dampen the vibration.   Second, increased bristle shedding in the later stage of a production run. Heavy, consistent bristle loss is almost always caused by incomplete machine calibration, not a design flaw. Achieving fully stable mass production requires a period of continuous fine-tuning to align parameters with your specific filament material, stiffness and ferrule dimensions. Once the machine is fully calibrated to your materials, bristle shedding will stay within the normal, acceptable range for routine production.   Third, setup for short filament production. For manufacturing brushes with shorter bristle lengths, we standardly apply cotton strips on the back filament baffle to better support and position the short filament bundle. These cotton strips have a service life of 3–5 months, and can be easily cut and resized on site for replacement. For customers with long-term high-volume short-brush production needs, we can also design custom-machined baffle components tailored to your exact ferrule specifications.   Finally, production of extra-small brush sizes. Our machine comes standard with 6.5mm and 8.7mm filament separating needles, which cover most mainstream flat and angled brush sizes. For smaller brush formats, smaller-diameter separating needles are available as optional accessories to ensure precise filament separation and clean, uniform brush edges.   At Hengyu Automation, we provide full lifecycle technical support for every machine we deliver. If you encounter issues not covered above, feel free to contact our after-sales team for targeted troubleshooting guidance.